1. Field of Use
This invention relates generally to a reusable two-piece fastener, comprising a hollow expandable/retractable body member and an associated externally threaded screw member, for releasably securing together a plurality of panels which have aligned apertures therein.
In particular, it relates to a body member of the aforesaid character which has a bore therein and resilient outwardly movable screw-engaging threads formed in the bore which accommodate axial sliding insertion of the screw member during body member expansion and then operatively engage the screw member to require rotational removal thereof during body member retraction.
2. Description of the Prior Art
U.S. Pat. Nos. 4,311,421 and 4,367,995 each disclose a fastener of the aforesaid character and each employs integrally formed screw-engaging projections on the wall of the bore of the body member to allow axial sliding insertion of the associated screw member which effects body leg expansion while requiring rotation of the screw member to effect its removal. This arrangement enables the two associated parts of the fastener (body member and screw member) to be conveniently fastened together prior to use so as to be readily available for use. However, the prior art screw-engaging projections which are constructed to enable axial screw insertion are relatively diminutive in size and fragile and do not ensure tight engagement between the body member and the screw member or tight securement of the panels. As a result, relatively small axial forces can cause axial separation of the two parts.